Add syntax highlighting infrastructure

- Introduced `HighlighterRegistry` with support for multiple language highlighters (e.g., JSON, Markdown, Python).
- Added `JsonHighlighter` implementation for basic JSON syntax highlighting.

kte-cloc

@@ -1,3 +1,9 @@
 #!/usr/bin/env bash
 
-ls -1 *.cc *.h | grep -v '^Font.h$' | xargs cloc -fmt 3
+fmt_arg=""
+if [ "${V}" = "1" ]
+then
+	fmt_args="-fmt 3"
+fi
+
+ls -1 *.cc *.h | grep -v '^Font.h$' | xargs cloc ${fmt_args}